Cell phones can be provided with an integrally mounted GPS receiver powered by the cell phone battery, the purpose of which is to detect position and to report position to a dispatcher or other type of office through the utilization of the cellular network. Such systems are illustrated in U.S. Pat. Nos. 5,598,460; 5,730,962; 5,649,059 and 4,833,477. In one embodiment, the report of location is done through a synthetically generated voice. This is done with a speech synthesizer which is driven by the NMEA0183 output of an onboard GPS receiver which, when decoded, provides a verbal string reporting latitude and longitude of the device.
As a recent development, the cellular phone can be made to report the latitude and longitude via a DTMF tones likewise transmitted over the voice channel, or alternatively transmitted over a control or separate channel.
These phones are typically provided with an emergency button, which when depressed activates the phone to provide position reporting after first dialing a predetermined number.
While it is indeed possible to provide wireless phones with activation, either with touchtones or via some other digital signaling system, these systems only work when the phone is turned on.
There are several scenarios which require a remote sensory switch to be able to activate a wireless phone. These are described in the aforementioned U.S. Pat. No. 5,598,460. It will, however, be appreciated that when an auxiliary activation is required, it may not be the case that the phone itself has been turned on or in fact that the GPS contained in the phone has been turned on. This provides a not-completely automatic system in so far as the user of the system must first provide a separate action to turn on the phone.
In the case of vehicle-mounted phones, it may not be the case that the phone itself is turned on when it is desired, for instance, to page the phone and to have it call a predetermined dispatch office. Such would be the case in, for instance, locating errant rental cars, waylaid trucks or other commercial vehicles or in fact locating individuals who have not turned on their phones. One example of the latter scenario is the case when the US Army trains troops. Typically, the training is over a month's period of time, in the woods or a remote terrain. According to the US Army, as many as six out of three hundred trainees can be lost in the one-month period. It is therefore important to be able to locate these trainees with the system that does not drain the battery. If the phone was kept on for an extended period of time, the battery would run down and the trainee would not be able to be located.
Likewise for prisoners, Alzeimers patients, children or individuals who do not wish to turn on the phone, their whereabouts can be ascertained by paging the phone if the phone where in fact turned on at the time.